Question about screen sizes for a Bead Mill Machine

Hi guys, I'm new to the coatings industry and still learning the ropes. I have a technical question regarding the separation screen inside a Bead Mill Machine. How do you determine the correct slot size for the screen? I know it needs to be smaller than the grinding beads so they don't escape, but if it's too small, won't it just clog up with the thick product? Is there a general rule of thumb for matching the screen gap to bead size?